This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A206580 #5 Mar 30 2012 17:23:03
%S A206580 0,1,3,4,6,8,10,12,18,20,24,26,30,42,46,50,52,56,60,70,72,74,78,86,92,
%T A206580 98,102,106,112,116,124,128,132,136,156,158,170,178,188,192,196,202,
%U A206580 204,212,236,242,250,266,272,274,276,278,286,292,294,312,318
%N A206580 Number of ones in the periodic part of the continued fraction of sqrt(n) for n in A206579.
%t A206580 t = {{2, 0}}; Do[If[! IntegerQ[Sqrt[k]], cnt = Count[ContinuedFraction[Sqrt[k]][[2]], 1]; If[cnt > t[[-1, 2]], AppendTo[t, {k, cnt}]]], {k, 3, 50000}]; Transpose[t][[2]]
%K A206580 nonn
%O A206580 1,3
%A A206580 _T. D. Noe_, Feb 29 2012